Ultrasonic and electrosurgical handpieces of various configurations to facilitate their usefulness and reliability have been used for a variety of surgical procedures. The combination of an electrosurgical and ultrasonic handpiece presents an number of challenges and problems. The most notable difficulty is the isolation of the radio frequency energy from the ultrasonic driving energy.
The handpiece requires a compact design that is facilitated by a piezo driver for the ultrasonic vibration. The use of piezo crystals such as barium titanate or lead titanate zirconate to drive the tool at ultrasonic frequencies is known in an Ultra product sold by Sharplan Laser and is manufactured by Fibrasonics Inc. That product is merely an ultrasonic tool with air cooling and without electrosurgical high frequency cutting and/or coagulation.
U.S. Pat. No. 4,674,498 has an electrosurgical system in which a blade is made to vibrate at a frequency sufficient to cause cavitation to take place as RF energy is simultaneously applied to electrodes on the blade for effecting cutting or coagulation. U.S. Pat. NO. 4,886,060 has an ultrasonic knife including high frequency electric coagulation. Cardiac floating isolation for the ultrasonic aspirator enables monopolar coagulation with the handle therefore as a completely passive conductor. The insulation circuit of the ultrasonic knife has specific dimensions to withstand RF energy to earth. Protecting the user with such circuitry neglects the preferred double insulation technique for maximum protection and double insulation has not been disclosed in the prior patents.
U.S. Pat. No. 4,903,696 has a generator that powers the electrodes of electrosurgical implements and at the same time the ultrasonic transducer for imparting vibratory motion to such implements.
U.S. Pat. No. 4,931,047 has a solution to incorporating a RF coagulating and RF cutting capability with a vibrating tip of an ultrasonic aspiration and fragmentation device. Switching is provided for the surgeon to use RF and/or ultrasonic as desired and without need of changing the surgical instrument. Insulation of the piezo driver from the high frequency electrosurgical energy is not known or in the devices available since the use of high dielectric electrical insulators in an ultrasonic transducer includes stress and structural problems heretofore unsolved.